1. Technical Field
The present invention relates generally to distributing file server loads in data processing system networks and in particular to discouraging end users from employing bookmarks to circumvent load distribution servers. Still more particularly, the present invention relates to preventing users from directly contacting a content server protected by a load distribution algorithm rather than the load distribution server.
2. Description of the Related Art
Internet content providers whose World Wide Web sites encounter large traffic loads frequently employ several servers to handle requests for data from their sites. In such cases where several servers are employed, the content servers frequently contain identical content and requests for files are routed to the least busy server. This is accomplished by routing file requests from a client to a central load distribution server at a publicized URL and letting it redirect these requests to the least busy of several content servers where the requested file is stored. The system should allow a client to send a file request to a load distribution server that sends the forwarded file request to a content server. The content server responds by sending the requested file to the client. In this way, the routing by the load distribution server is designed to protect any one content server from being overloaded with file requests.
At the same time, almost all hypertext systems include a facility for providing easy and fast access to a user's favorite pages on the World Wide Web (“web pages”). Such a facility is often referred to as a hotlist or a bookmark list. Existing systems depict the bookmark list as a textual list of web page titles (called “bookmarks”) in a pull-down menu or other list within a web browser. A typical bookmark list also permits users to add new bookmarks to the list, update the titles associated with the web pages, and display the updated lists. Many browsers also allow a program to automatically edit this list for the user.
An example of how bookmarks are created, displayed, updated, and used to access web sites is demonstrated below using the Netscape Navigator™ browser from Netscape Communications Corporation (“Netscape”). Bookmark creation is typically user initiated. First, the user launches a browser program for browsing the Internet. FIG. 9 illustrates the December 1999 home page of IBM as displayed in the web page viewer section 900 of the browser 902.
In order to save the IBM home page as a bookmark, the user selects a bookmarks menu item 904 from a menu bar 906. FIG. 10 illustrates a state of the browser 1010 after the user has selected the bookmarks menu item 1012. As FIG. 10 illustrates, selection of the bookmarks menu item displays a bookmarks pull-down menu 1000. The bookmarks pull-down menu consists of two primary components: a command section 1002 and a bookmarks section 1004. The command section initially displays an “Add Bookmark” command 1006 and an “Edit Bookmarks” command 1008. In general, the bookmarks section displays all previously saved bookmarks. The bookmarks section displayed in FIG. 10 illustrates a nine item list of previously saved bookmarks. In order to save the current web page as a new bookmark, the user selects the “Add Bookmark” command 1006 from the command section 1002.
FIG. 11 illustrates a state of the bookmarks pull-down menu 1000 after the IBM home page has been added as entry 1100. The process of displaying a web page associated with a bookmark is also user initiated. FIG. 12 illustrates the Netscape browser user interface as it displays the home page of Texas A&M University. The example which follows illustrates how a user, who is currently displaying Texas A&M University's home page on his browser, can use the IBM bookmark 1300 (FIG. 13) to display IBM's home page using a bookmark rather than another method of navigation such as hypertext linking or typing the URL. In short, the user positions a pointing device, such as a mouse pointer, over the IBM bookmark, and actuates a mouse button to select the bookmark. In response to the user's selection, the browser displays IBM's home page as was originally done in FIG. 9.
Existing bookmark methods allow the user of a World Wide Web site to bookmark any page or server desired. Because of this, users intending to return to a particular piece of content frequently bookmark the server providing the content, one of the several content servers containing identical files previously described, rather than the central load distribution server that is designed to redirect file requests to specific servers and protect any one server from an overload of traffic. This leads to the situation where requests flow to a given server without regard to how busy that server is and the server can be overloaded by incoming requests, thereby defeating the purpose of the central load distribution server.
The problem thereby created is illustrated in FIG. 14, where the second and fourth clients 1412 and 1410 have bookmarked the load distribution server 1400 and the first and third clients 1406 and 1408 have set their bookmarks to refer to the server 1402 that actually provides the content. As can be seen from the drawing, the second and fourth clients 1412 and 1410 send their file requests 1418 and 1420 to the load distribution server 1400. The load distribution server 1400, as expected, redirects one of the requests 1426 to the first content server 1402 and the other of the requests 1422 to the second content server 1404. This arrangement should result in balanced loading of the two servers and protect any one content server from being overloaded with file requests.
However, that the first and third clients 1406 and 1408 have also sent their file requests 1414 and 1416 to the first content server 1402. This leaves the first content server sending out three files 1436, 1430, and 1432 to the first, third, and fourth clients 1406, 1408, and 1412 while the second content server 1404 sends only the second file 1434 to the second client 1410. The first content server bears 75% of the load and the second carries only 25% of the load. Because of this, users of the first content server 1402 are likely to experience perceptible degradations in the performance of the server as well as the risk of lost file requests. The owner of the servers suffers the risk of a server crash as well as the perception that his site provides poor service in the form of loss of or delays in processing file requests. Both users and server administrators suffer real and non-trivial consequences from the ability of users to bookmark content servers.
It would be desirable, therefore, to be able to prohibit the user from accessing the several content servers where identical files are stored without first accessing the central load distribution server that allots the work to the several content servers. It would further be advantageous if the method of prohibiting the user from accessing the several content servers automatically referred him to the central server. Lastly, a further advantage would be gained by modifying the user's bookmarks to insure that his next attempt to access the same World Wide Web page was routed through the central load distribution server.